Around 8 or 9/631, ʿAlī (a) led a group of 300 horsemen to the al-Nakhaʿ clan and other neighboring clans. Following their successful defeat and the establishment of a peace pact, he returned to the Prophet (s). Furthermore, after Khālid b. al-Walīd’s unsuccessful attempt, the Prophet (s) assigned ʿAlī (a) with the task of traveling to Yemen to invite the Hamdān tribe to embrace Islam. ʿAlī (a) successfully conveyed the message of Islam, and as a result, all members of the Hamdān tribe embraced the faith and converted to Islam. Afterwards, ʿAlī (a) gained dominance over the Madhḥij tribe and engaged in adjudicating their cases. Upon Amīr al-Muʾminīn’s allocation of a portion of the spoils for himself, Khālid b. al-Walīd voiced his criticism of ʿAlī (a), conveying it to the Prophet (s) via Burayda b. Ḥuṣayb al-Aslamī. In response, the Prophet (s) said, “[O Burayda!] What is permissible from the spoils for me is also permissible for him. ʿAlī is the best person for you and your tribe, and he is the best person I leave behind for all people after me. O Burayda! Refrain from harboring hostility towards ʿAlī, for if you do so, it will incur the anger of God upon you.” Furthermore, according to some accounts, the Prophet (s) subsequently said, “he is your guardian after me.”

In Sunni sources of hadith, the event is recorded with various narrations as transmitted from Burayda b. Ḥuṣayb, each with different wording. As the bearer of Khālid’s letter, Burayda spoke ill of ʿAlī (a) in the presence of the Prophet (s). The Prophet (s) became furious and admonished, “Do not slander ʿAlī, for he is from me and I am from him. He is your guardian after me.” In another hadith, Burayda quotes the Prophet (s) as saying, “Whoever I am the guardian of, ʿAlī is also his guardian.” In yet another hadith, the Prophet (s) said, “O Burayda! Am I not more entitled to the believers than they are to themselves?” Burayda replied, “Yes.” The Prophet (s) then declared, “Whoever I am the master of, ʿAlī is also his master.” Furthermore, Burayda recounts the event by stating, “I had resentment towards ʿAlī (a) in my heart. Suddenly, the Prophet (s) approached me and asked, ‘O Burayda! Do you bear animosity towards ʿAlī?’ I replied, ‘Yes.’ Then he said, ‘Do not bear any animosity towards him, for ʿAlī’s portion of the khums is greater than this’.“

 In 10/631, the Prophet (s) sent ʿAlī (a) to Yemen for the second time, directing him to establish a camp in the Qubāʾ region and await the arrival of his companions. The Prophet (s) personally wrapped a turban on ʿAlī’s head, saying, “When you reach their land, do not engage in fighting unless they initiate it against you ... Invite them to embrace the declaration ‘There is no god but Allah.’ If they accept, invite them to establish prayers, and if they accept, invite them to give charity to the poor. If they agree to all these, refrain from asking anything more from them. I swear by God that if through your efforts, one person is guided, it would be better for you than [possessing] everything on Earth.” ʿAlī (a) advanced with a contingent of 300 horsemen. In the vicinity of Yemen, they acquired some spoils, which ʿAlī (a) entrusted to Burayda b. Ḥuṣayb al-Aslamī. Initially, ʿAlī (a) extended an invitation to them to embrace Islam, but when they responded by launching a barrage of arrows, he led an assault with 20 warriors. Consequently, they repelled the attackers, and ʿAlī (a) renewed his call to Islam. This time, some of them accepted and embraced the faith. Subsequently, some of ʿAlī’s companions requested the distribution of the spoils, but he responded, “We will present the khums possessions to the Prophet so that he may distribute them accordingly.” Imam ʿAlī (a) hastened his return from Yemen to join the Prophet (s) near Mecca in order to participate in the Hajj rituals ahead of his companions. Upon the arrival of the Muslim caravan, Amīr al-Muʾminīn (a) noticed that, based on the requests of certain army members and commanders, Abū Rāfiʿ had distributed the spoils among them, resulting in their adorning themselves with new garments. Rebuking Abū Rāfiʿ, ʿAlī (a) commanded his army to take off the garments they had acquired. This action displeased some of them, who subsequently expressed their grievances about ʿAlī (a) in the presence of the Prophet (s). The Prophet (s), in support of ʿAlī (a), addressed the complainants, saying, “Do not voice your complaints against ʿAlī. I swear by God that he is strict on the path of God.”

This incident occurred during the final expedition led by ʿAlī b. Abī Ṭālib (a) to Yemen. Based on the hadiths transmitted by ʿAmr b. Shās regarding the complaints against Amīr al-Muʾminīn (a), it can be inferred that ʿAlī (a) undertook three expeditions to Yemen. In the initial expedition, the incident involving Khālid b. al-Walīd’s letter took place, while in the final expedition, which coincided with the Prophet’s presence in Mecca, the episode involving the distribution of the khums possessions by Abū Rāfiʿ unfolded. However, in the narration of ʿAmr b. Shās, neither of these two stories is mentioned. According to ʿAmr, “I accompanied ʿAlī to Yemen, where I faced an injustice that led to me harboring resentment towards ʿAlī. Upon returning to Medina, I expressed my complaint in the mosque, and through word of mouth, it eventually reached the Prophet (s). The following day, when I went to the mosque, the Prophet (s) looked at me and said, ‘O ʿAmr! You have caused me pain.’ I responded, ‘O Messenger of God! I seek refuge with God if I have caused you pain.’ The Prophet (s) affirmed, “Yes, whoever hurts ʿAlī has hurt me.”

ʿImrān b. Ḥuṣayn states, possibly referring to another expedition to Yemen, that the Prophet (s) appointed ʿAlī (a) as the leader of an expedition. Four of his companions became discontented due to an incident and planned to lodge a complaint against ʿAlī (a) upon their return to Medina. In response, the Prophet (s) intervened and said, “Leave ʿAlī alone. Indeed, he is from me and I am from him. He is the guardian of all believers after me.”